OJ 16"x15" for the 550hp boats --FINALLY--

[Live to surf]

Will OJ take orders for this prop?


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[nyryan2001]

Yep, call Eric at OJ.


So the 16"x15.5" performed terrific. Dropped RPMs another ~150+ across the board.

Surfing my standard wave today at whispery quiet 2625rpms.... vs 2950-3100 on the OEM 15x14.25" prop.

Was still able to launch out of the hole like a rocket, and the engine was still able to achieve 5450 RPMs.

It could handle a 16x16.

[philb]

Ryan, can you give us the RPM at 23Mph with NCRS at 5 please?

[nyryan2001]

Yep, with or without 2850 OEM ballast?

[philb]

With full OEM please and also if you've run extra at 23mph.

[nyryan2001]

Ok here you go. 23mph full 2850lb OEM ballast plus ~5-700ish lead and extra batteries. NCRS at 5, ~3250rpms. This would have bee in the 3600-3700 range for the OEM 15x14.25 prop. If you drop the NCRS down to 0, same weights, you see ~3000rpms.

[sja]

In my 2013 G23 550, it takes about 200# lead in the port side trunk to compensate for the prop torque (plus a passenger of weight equal weight to the driver sitting in port side seat). You commented above that the prop torque was greater with the larger prop. Do you know how much more weight is needed in the port trunk to compensate at 23mph?

[bradw]

What had this prop done to the fuel consumption?

[nyryan2001]

Well I've only got one data point as far as fuel usage compared to last summer. So this weekend I averaged 7.3GPH. Not extraordinary in just the number... But I spent a good majority of the weekend hammering it a full speed, fast heavy launches with full ballast...surfed heavy for 75 mins heavy yesterday, roughly 4100lbs. Where ordinarily I would be in around ~9gph average for a weekend of that type of use.

It's very early.... But it looks like it'd save in the neighborhood of ~1.5-2gph average.

[nyryan2001]

Sja- I'd estimate it'd need 200-300lbs on the port side, with a 200lb driver alone in the boat to overcome the prop torque at 24mph. Rough estimate here.

It feels like it added 2-300lbs to the starboard side while surfing at 11.6 also.

[JoeA]

Ryan,

How many hours did you run this weekend to average your gas consumption at 7.3 GPH?

Do you have a 16x16 coming to test or are you suggesting the 16x15.5 is the go to prop for G23 550 boats

[nyryan2001]

3.3hrs at 24.3 gals used. Again only one data point to compare.... but as a benchmark, my harder weekends(9-10logged specifics from 2014, from the same Shell gas pumps) last summer were in the 9gph average range, this weekend was definitely in the heavier category, multiple 5400rpm WOT runs, heavier wakesurfing. I am reluctant to oversell the savings in GPH... but if you look at RPM reduction... and so far my one data point at the pump... at a minimum you save 10-15% fuel.... maaaaaybe near 20%, due to the lower RPMs, and really depends on how you use your boat. we'll see. but the performance and RPM reductions are undisputable. I think one of this biggest savings areas is on launches... you don't need to crazy over-rev to 4000+rpms to achieve your speed...this weekend while surfing 4000lbs...I would rev to 3100rpms launching as fast as I could... it would lurch forward very fast, and settle to the surf cruise RPMs of 2800ish. those over-revs on launches guzzle fuel, this help minimize those.

I don't know if there is a 16x16 coming yet, haven't talked to Eric yet. With full 2850OEM + ~500ish ballast... the G straight launches out of the water still on the 16x15.5 and still is able to reach 5450rpms. I'm not trying to waste folks' time, but I think a 16x16 is warranted with the results seen on the 16x15 and the 16x15.5.... no signs of it being overprop'd yet.

By the way, anyone want to test to see how many times a cotter pin on a prop shaft can bent, straightened and be reused? lol

[bradw]

Be interesting to see how the fuel consumption goes over say ten hours..... I recon my G23 with just factory ballast was using 9GPH and more with the 300kgs of lead i threw in late in the summer.

I have an R type clip on my prop instead of a split pin, ill take a photo next time I have my boat out.

Any word on the prop/box/motor combos for 2016?

[nyryan2001]

Brad, I think you are going to see significant performance increase and fuel savings. I talked to Eric.... I should have the 16x16 for testing over this holiday weekend... and I'm sure to burn at least a full tank on it. I will report back how it does.

[Kenv]

Great write up nyryan. Interesting and educational read. It's nice to see that options are available to get peak performance over "stock" Quick question...are all of the G's RHand rotation on the props? I have a new G21 and will hit the water with it for the first time this weekend. Don't remember if it was left hand or right hand. Thanks. Ken